Radio signaling apparatus



- y 7 1". o. PARKIN RADIO SIGNALING APPARATUS Filed Dec. 2. 1921 fuse in measuring fr Patented *May 31, 1927.

THOMAS DIXONQARKiN, orcnnmvisronn, n'nena vn assienon'zro Rania oon'rona 'rIor'r OF AMERICA, A consort-ArronorfnELAwAnEfi i M1. l n

ream .s ar ite scream-cit Application filed Dec ember 2', win, Serial no. 5 19,5511, and in ,GreatBrita in Jaiiuary 31,1921. V 1;: ne M. 151,: 3:.-' Luca,- .1 i i.,;. 1. .u .u. pvAt/ w. .3 v

The object of this invention is (an im proved c1rcuitwh1ch'"may be'us'e'd forfactuat- 'ing 'a calling or alarm device or recording signal The may be adapted "for 'quen'cies' 'According'flto{thisinvention a receiver is coupled preferabl cored telephone transformer to the gridfilament circuit of a three electrode valve in series with the anode of which is a tuned oscillatory circuit and to a point in the inductance of this circuit is connected through the coil of a'relay the anode of'a second valve in the grid filament circuit of which is an inductance'coupled 'to the first named inductance. The coupling between the two inductances together with the leak produced by the first valve is so adjusted that the sec ond valve does not normally generate oscillations, but'is kept steadily on the verge of oscillation when no signals are being received. On the incidence of waves of 'the' v predetermined frequency the currents resulting therefrom are magnified by the 'firstvalve and thus a difierenceof potentl'al is set up on the two sides of the oscillatory circuit in which large currents therefore circulate. Consequently the second valve generates oscillations, the energy to support the oscillations being drawn from the high tension battery and the. relay is actuated to give the alarm. I Y

Upon cessation of the signal the adjustment of the coupling and the leak contributed by the first valve are sufficien't'to quench the oscillation set up by the second valve,

the current through the relayfalling to its original value and ceasing to operate the relay. 1

In some cases the anode circuit of the sec- 0nd valve does not include a portion of the inductance of the oscillatory circuit, but. the former arrangement is to be preferred.

Preferably a. galvanoineter is included in series with the relay coil for the purpose of noting the change of current.

Theinvention is illustrated by the acco n panying drawing in which Fig. 1 embodies the invention and Fig. 2shows a modification.

the grid circuit of valve V is the secondary of a transformer T, the primary of which iianod'e dffthe firs-twelve a d the s'io'n 'batery HTJF Coupledfto t .L is a' sec nd tweienj the T 13 .b mi aas "of an iron i e ct ed" thr throi'iglr'a point P in the inductance vL.- Then a sufficient current flows through the coil of re- In Figure 1, V, V, are the two valves. In

an oscillatory circuit connected between thelay R owing to the oscillation set up by ode of valve V" instead of being connected to an ad ustable point in the inductance L is permanently "connected to the side of, circuit CL which is remote from the anode of the first valve. This circuit is not arranged to be on the verge of oscillation. inc dence of wavesof predetermined fre- On the-- quency the currents due to thefsignal are magnified by thefirst valve and large curs rents circulate in the tuned circuit CL.

These currents induce a difference of potential at the terminals of L which is rectified'by the second valve, the consequent increase of mean anode current being'sufficient to work the relay. V i 1 Thesecircuits may be used as recording circuits for wireless telegraph signals, especially continuous wave signals, a recorder of knowntype being substituted for the bellB.

Signals are received and in the case of continuous waves are heterodyned to a predetermined frequency andapplied to the is tuned to the predetermined frequency or in the case of sparksignals to the spark fre quency The relay will now follow as precode and will operatethe local circuit containing the recorder. i q

Either circuit mayalso be used as a frequency meter. The inductance L being known, the condenser can be; calibrated in frequencies. If an alterating difference of potential be applied to the terminals of terminals of transformer T. v The circuit CLf V viously described the signals of the Morse 1 transformer T- and the condenser beadjusted, a maximum current will flow through the galvanometer G when the applied frequenoy equals the frequency to which LC is tuned.

Having described my invention, What I claim is: p I I 1. The combination of two three-electrode valves'one oi Which is on the point of self- -oscillation When no oscillations are impressed on it means for applying incoming oscillations to the grid circuit of one valve, an oscillatory circuit adapted to be tuned to a desired frequency connected to the an ode of that valve and connected to the grid circuit of the second valve by means of an adjustable tap and a relay coilconnected between the oscillatory circuit and the'anode of the second valve.

' 2. The combination or a three electrode valve, means for applying incoming oscillations to the grid of saidvalve, an oscillatory circuit connected inthe anode circuit of said valve, a second three electrode valve havingits grid circuit connected to said osvalves, means for applying incoming oscillations to the grid circuit of one valve, an osclllatory circuit comprising an lnductance and a capacity in parallel, means for couplingthe grid circuit of the other valve to said 'inductance, a connection from the an ode of the last mentioned valve to an adjustable point on said inductance and a relay cooperating With said connection; Y THOMAS DIXON PABKIN. 

